chords can be made of any of the notes in the key. for instance there are ninth chords which have the root 3rd 5th 7th and 9th ( the 9th is a second that has a higher pitch than the 7th) i dunno really y this matters but that is what it is. if u want to get more expresive chords i recomend learnin the main types of 7th chord

Majour seventh root, 3rd, 5th, 7th
minor seventh root, minor 3rd, 5th minor, 7th
dominant 7th or 7th chord root, 3rd, 5th, minor 7th
diminished 7th root, minor 3rd, diminished 5th, minor 7th